Manual shift transmissions include multiple pairs of gears meshing with one another. At least one gear of each pair is formed as a loose gear, which can be coupled to a shaft carrying it in a positively joined manner with the help of a gear shift sleeve in order to establish a torque flow between input and output of the transmission via the gear pair concerned. In order to be able to realize multiple gears in a manual shift transmission, multiple gear pairs and typically also multiple gear shift sleeves are required which have to be moveable independently of one another. The actuators required for driving the movements of the various gear shift sleeves occupy installation space, which renders the transmission as a whole bulky.
US2008/0134819A1 proposes to control the movement of two gear shift sleeves mounted on a same shaft with the aid of a gear shift drum. On its circumference the gear shift drum carries two slotted control links, which interact with a gear shift follower. In each case the gear shift followers act on one of the gear shift sleeves. The pitch of the slotted links relative to the axis of rotation of the drum determines the extent and direction of the movement of the gear shift follower brought about by a rotation of the drum. Different courses of the slotted links make possible different movements of the two gear shift followers assigned to these. Although a drum is able to control the movements of two gear shift sleeves independence of the movements from one another is not achievable since at any point of the drum the possible movements are predetermined in a fixed manner and merely the direction of the rotation can be selected. Since all required combinations of positions of the gear shift sleeves have to be depicted through the course of the cams and the pitch of the cams must not be too large so that no self-locking can occur, the space requirement of this conventional shift control mechanism is also substantial.